The present invention generally relates to firearms, and more particularly to an improved composite firearm barrel.
The barrel of a firearm is in essence a pressure vessel that is subjected to heat and forces of combustion generated by igniting a cartridge powder charge when the firearm is discharged. Accordingly, steel has been the material of choice for firearm barrels because its mechanical properties allow it to repeatedly withstand numerous cycles of discharging the firearm. But barrels made of entirely steel tend to be heavy, which may make steel-barreled firearms cumbersome to carry for long periods of time or to hold steady during shooting competitions. One attempted solution to produce lighter barrels has been to use aluminum barrels provided with hard-coated or plated bore surfaces for the bullet path. These barrels may be expensive to manufacture and the thinly coated bores surfaces may wear away over time. Composite firearm barrels, defined herein as barrels made of two or more different components, are also known. Some of these barrels include steel inner tubes with outer sleeves or shells made of lighter-weight material, such as aluminum or synthetic plastic resins. Joining the multiple components together to form a secure bond capable of withstanding repeated firearm discharges, however, has been problematic. The outer sleeves have sometimes been attached to the inner steel tubes with adhesives, press-fitting, screwed or threaded connections, sweating or brazing, and by casting. These production techniques may result in composite barrels that may separate over repeated cycles of discharging a firearm due to inadequate bonding or coupling between the inner tubes and outer sleeves or shells. Some known designs may also require multiple fabrication steps and be labor intensive to produce, thereby sometimes making manufacture of these conventional composite barrels complicated and expensive.
Accordingly, there is a need for a light-weight composite barrel that is simple and economical to manufacture, and yet provides a strong and permanent bond between the inner and outer components.